Covering for x-ray apparatus



Dec. 1934- A. UNGELENK 1,983,327

COVERING FOR X-RAY APPARATUS Filed April 11. 1930 Inventor-z Alfi ed Ungelenk, WM-

- Hts \Attomgy.

Patented Dec. 4, 1934 1,983,327 COVERING j-FoR X-RAY APPARATUS Alfred Ungelenk, Thuringia, Germany, assignor to General Electric Company, a. corporation of New York Application April 11, 1930, Serial No. 443,586 In Germany April 19, 1929 4 Claims.

The present invention relates to X-ray apparatus and more particularly to the covering which encloses the X-ray tube.

In order to absorb undesired stray rays which unavoidably are produced at the target of an X-ray tube, it is the practice to enclosethe nvelope completely in a covering of suitable X-ray absorbing material except for an aperture through which the desired rays emerge. This covering usually comprises two portions, one part being constituted of a plurality of concentrically arranged metallic cylinders or a single cylinder positioned in such a manner as to surround the discharge zone thereby to intercept the radially directed rays. The other part may take the form of cylinders which extend the entire length of the envelope and are designed to absorb that portion of the undesired rays which is propagated longitudinally of the target. When employing a pro- 0 teotive structure of this sort, it has been found sometimes during operation that sparks are formed in the space between the inside of these insulating coverings and the outside of the X-ray tube. In the event that the envelope consists 5 partly of metal necessitating metal to glass seals, the sparking may be sufiiciently severe to break down the seals and cause rupture of the tube.

I have discovered that when the insulation 3'0 covering is positioned a substantial distance away from the tube, this difiiculty may be avoided. The invention will be better understood when reference is made to the following description and the accompanying drawing in which the 5 figure illustrates partly in section and partly diagrammatic, an X-ray tube improved in accordance with my invention.

In the drawing, numeral 1 designates the glass envelope of an X-ray tube terminating in reentrant stems 2, 3 which constitute supports for the anode 4 and cathode 5 of usual and well known design. The discharge zone between the electrodes is surrounded by a cylinder 6 of suitable refractory metal which may comprise the metal section of the envelope as shown. This metal cylinder is provided with a glass insert 7 at a position opposite the target which serves as a window for the X-rays. On the exterior of the tube and in opposed relation to the cylinder 6 .3 there is an apertured jacket 8 of lead or equivalent metal for absorbing the radially directed rays which may pass through the cylinder 6. The jacket is fitted within a metallic casing 9 of brass or the like which may serve as a support for the apparatus in the well understood manner. The casing is provided with an opening 10 which registers with the aperture in the jacket 8 and the window in cylinder 6.

In order to maintain the cylinder 6 at substantially ground or any other desired potential, 0 there may be provided one or more conductors 11 joined to the envelope and connecting the cylinder to the outer metal members. The covering for absorbing the rays transmitted longitudinally of the target takes the form of cylin- 3"5 ders or sleeves 12 which may be made of a phenolic condensation product and impregnated or coated with lead oxide. The cylinders are of sufficient thickness to offer rigidity of shape and may be secured at their inner edges in any suitable manner within a circular slot 13 formed between the lead jacket and brass casing, as shown.

In accordance with my invention the covering including the jacket and casing is made substan- '75 tially larger in diameter than the envelope so that when mounted about the latter by means of suitable spacers (not shown) there is presented an annular air space of appreciable width. This air space serves the twofold purpose of precludg ing in a substantial degree the formation of sparks between the envelope and the covering and in addition of providing free air circulation along the entire length of the tube. The fact that the envelope fits loosely within the cover- 35 ing also oifers the advantage of allowing the tube to be readily removed from or placed within the covering. In order further to reduce the danger of breakdown particularly at the metal to glass seals, it may be desirable to extend the lead 5 jacket beyond one or both edges of the metal cylinder 6.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, an X-ray tube and a pro- 5 teotive cover for the envelope of said X-ray tube, said envelope consisting in part of a metal cylinder which surrounds the discharge zone, said cover comprising a cylinder of X-ray absorbing material surrounding the envelope and spaced m therefrom a substantial distance to permit free circulation of air from the exterior of said cylinders into the space between said cylinders, the cylinders being maintained at substantially the same potential.

2. In X-ray apparatus, the combination of an envelope which consists partly of glass and partly of metal, a covering member comprising a metal cylinder which surrounds the metal portion of L the envelope and a plurality of cylinders of in- 1*10 its sulation material which surround respective glass portions of the envelope, said covering member being spaced from the envelope a substantial distance and being open at its ends, and said metal cylinder extending beyond both ends of the metal portion of the envelope.

3. In combination, an X-ray tube and a protective cover for said X-ray tube whose envelope consists in part of a metal cylinder which surrounds the discharge zone, said cover comprising a cylinder of X-ray absorbing material surrounding the metal portion of the envelope and spaced therefrom a substantial distance to permit free circulation of air from the exterior of said cylinders into the space between said cylinders, and

ALFRED UNGELENK. 

